transition from paleogene normal calc-alkaline to neogene adakitic-like plutonism and

Transition from Paleogene Normal Calc-Alkaline to Neogene Adakitic-Like Plutonism and

Newfoundland Neogene sediment drifts: transition from the Paleogene greenhouse to the modern icehouse

This workshop brought together specialists from various fields to develop a drilling proposal to fill the “Oligo-Miocene Gap” that exists in our understanding of the functions of Earth’s systems. We propose to establish the first continuous high-deposition record of the Oligo-Miocene through new International Ocean Discovery Program (IODP) drilling in the North Atlantic to allow the development...

The first hyaenodont from the late Oligocene Nsungwe Formation of Tanzania: Paleoecological insights into the Paleogene-Neogene carnivore transition

Throughout the Paleogene, most terrestrial carnivore niches in Afro-Arabia were occupied by Hyaenodonta, an extinct lineage of placental mammals. By the end of the Miocene, terrestrial carnivore niches had shifted to members of Carnivora, a clade with Eurasian origins. The transition from a hyaenodont-carnivore fauna to a carnivoran-carnivore fauna coincides with other ecological changes in Afr...

Distribution and geochemical variations among paleogene volcanic rocks from the north-central Lut block, eastern Iran

The Lut block in eastern Iran is a micro-continental block within the convergent orogen between the Arabian, Eurasian and Indian plates. Large areas of the north-central, eastern, and western Lut block are covered by volcanic rocks of Paleogene, Neogene and Quaternary age.  Peak volcanic activity took place in the north-central part of the Lut block during the Eocene, and then dramatically decr...

Significance of hornblende in calc-alkaline andesites and basalts

Hornblende occurs in some andesitic and basaltic rocks of calc-alkaline affini1y, where it is commonly associated with olivine. The texture, eruption history, and composition are interpreted to indicate that hornblende commonly forms as a product of reaction between olivine and basaltic and andesitic liquids. The natural hornblendes probably formed within the crust at temperatures between 960o ...

Origin and magmatic evolution of the alkaline extrusive rocks of Neogene from Nehbandan-Assagie region, eastern Iran

The alkaline extrusive rocks of Neogene from Nehbandan-Assagie region, eastern Iran, include basanite, hawaiite, mugearite and benmoreite. Relatively low Ni and Cr contents and Mg-numbers of basanites are indicative of olivine and clinopyroxene fractionation from their relevant primary magma. Decreasing of CaO, TiO2, FeOt, HREEs and MREEs with increasing SiO2 indicate fractional crystallization...